This invention relates generally to knob control devices; and more particularly to control knob devices including force feedback and/or additional input functionality. Control knobs are used for a variety of different functions on many different types of devices. Often, rotary control knobs offer a degree of control to a user that is not matched in other forms of control devices, such as button or switch controls. For example, many users prefer to use a rotating control knob to adjust the volume of audio output from a stereo or other sound output device, since the knob allows both fine and coarse adjustment of volume with relative ease, especially compared to button controls. Both rotary and linear (slider) knobs are used on a variety of other types of devices, such as kitchen and other home appliances, video editing/playback devices, remote controls, televisions, computer interface controllers, etc. There are also many types of knobs that allow push-in or pull-out functionality to allow the user additional control over a device.
Some control knobs have been provided with force (kinesthetic) feedback or tactile feedback, which is collectively referred to herein as “haptic feedback.” Haptic feedback devices can provide physical sensations to the user manipulating the knob. Typically, a motor is coupled to the knob and is connected to a controller such as a microprocessor. The microprocessor receives knob position and direction signals from the knob sensor and sends appropriate force feedback control signals to the motor so that the motor provides forces on the knob. In this manner, a variety of programmable feel sensations can be output on the knob, such as detents, spring forces, or the like.
One problem occurring in control knobs of the prior art is that the knobs are limited to basic rotary and/or push-pull motion. This limits the control options of the user to a simple device that does not allow a variety of selection options. Most mechanical knobs have a very limited feel, i.e., they do not have the ability to feel different depending on the interface context. In addition, if force feedback is provided on the knob, the limited control functionality of the knob limits the user from fully taking advantage of the force feedback to provide more control over desired functions. Furthermore, many of the well-known force feedback sensations are inadequate for dealing with some of the selection functions required from a knob, where often complex control over functions and options must be provided with limited knob motion.